Blowoff valve mechanism



Jan- 33 1950 c. G. LEARNED ETAL 2,495,901

BLOWOFF VALVE MECHANISM Filed May 4, 1944 Patented Jan. 3l, 195.0

UNITED STATES PATENT OFFICE f @#195901 i' I BLoWoF VALVE MECHANISM- charles* G. Learned and EawinL. cull, ohieg, Ill.,v as signors to The Okadee Company, Chicago, Ill., a corporation of Illinois Y "appiictioiiinay 4, 1944, serial No. 534,044

"1`c1aim`. (01.'137-139) The invention relates toblow-oi valve mechanism for lluid under pressure', such as steam.'

One object of the invention" is to provide -an improved blow-off valve mechanismor system which is controllable for blowing off steam by exhausting steam therefrom'through aV remote operators valve.

Another object of the invention is to provide an improved blow-off valve mechanism which issimple in construction, eiiicie'nt in operation, and controllable for'blowing off steam through an operators valve to which 'steam in restricted flow is delivered from the inlet chamber of the blowoli valve.

Another object of the invention is to provide blow-oil valve mechanism of this type which includes means for locking the blow-01T valve in its closed position in thev event of leakage'in the pipe-line between the control valve and the blowoff valve.

@ther objects of the invention will appear from the detailed description;

The invention consists in the several novel features hereinafter set forth and' more particularly defined by the claim at the conclusion hereof.

In the drawings: Fig. 1 is aside Yelevation of a blow-off valve mechanismv embodying the invention including the operators valve forI controlling the blow-oi operations. Fig. 2 is a longitudinal section of the blow-01T valve. Fig. 3 is a section taken on line 3--3 of Fig.`2.

The invention is exemplified with a blow-off valve which comprises a casing 6 which is provided at its back with an inlet duct 1; an integral flange 8 at the rear end of the duct 'I whereby the casing may be secured to the boiler or any other suitable connection for blow-01T purposes; an annular chamber I8 into lwhich iluid from the inlet duct passes; a cylinder 9 which extends from one side of the inletchamber I8; a ring I6 secured in a wall II at-tne opposite side of the inlet chamber I8 and provided with aconical valve-seat I; and an outlet chamber 20 formed in one end of the casing to whichthe stream viiows through ring IS and which has connected thereto a discharge pipe 2| for conducting the blow-oi steam to any point-where 'it is desired to'discharge the stream. A head I0 is screw-threaded into one end of the casing body and forms a closure for the outer end of the cylinder 9.

A valve-pistonl I'I controls the blow-olf of steam from inlet chamber I8 to the outlet chamber 20. A compression coil spring 23 is confined in a socket 24 in the head l0 and a socket 25 in the piston II for normally pressing the closure end I4 of the piston against the seat I5 and to cut oil' the discharge of steam from inlet chamber I8'to the outlet chamber 20. The valve-piston II comprises a cylindrical member or portion I2 which is slidably fitted in the cylinder 9 at oneside of the inlet chamber I8, an integral cylindrical member or portion I3 which is of lesser diameter than the cylindrical portion I2 andv extends across the chamber I8, and is provided with a tapered end I4 which functions as a closure which is engageable with the valve-seat I5 on the ring I6 for cutting off the ow of steam from inlet chamber I8 to outlet chamber 20. Between the cylindrical member l2 of greater diameter and the cylindrical member I3 lof lesser diameter the piston II is provided with an annular side portion |22 which isexposed to the pressure of the steam in the annular inlet chamber I8. The outer side |21 of piston-member I2 has a greater area exposed to pressure in the cylinder 9 than the opposed pressure area on the annular side portion I2a, so that when the pound pressure of steam against side portion I2a and side I2b is equal, preponderating pressure will be exerted against the side I2b of the piston for holding it closed against the seat I5.

A small diagonal port 26 leading from the periphery of theV piston member I3 to the socket 25 in the piston provides a passage for the restricted flow of steam from inlet chamber I8 into the cylinder 9 and against the outer side I2b of the'piston. This restriction of flow from inlet chamber I8 to the outer end of cylinder 9 is sufcient to cause the steam pressure against the side portion I2a of the piston to shift the piston against the force of spring 23 when steam pressure against the side' I2b of the piston is removed by exhausting the steam from the outer end of cylinder 9. K

The invention contemplates controlling the operation of the valve piston to its open position for blowing off the steam by exhausting steam from the outer-'end Aof the cylinder 9, by an ordinary remotely located operators valve 29 which -is eommunicatively connected by a pipe 28 to the outer end of cylinder 9 and is adapted to discharge the steam through an outlet 30 to atmosphere.

The "operation will be as follows: When the op;

erators valve'29 is closed, steam under pressure enteringfthe chamber 'I8' in the casing Gthrough duct l WiHfhWthroush the, restricted duet a into the cylinder 9 and pipe 28. The pressure of the steam in the cylinder 9 between and against side I2b of valve piston II will hold the valve piston closed against the seat I and supplement the force of the spring 23 and prevent blow-off of steam from chamber I8. When the operator desires to blow oi steam, he will open valve 29. The steam in the cylinder 9 will escape freely via pipe 28, valve 29, and the outlet 30. This free discharge will be at a greater rate than the flow through the restricted orifice 26 so that there will be no substantial pressure of the steam against the side I2b of valve piston II. The pressure of the steam in the annular chamber I8 will be sufcient to move the valve piston II outwardly against the loading of spring 23 and cause the end I4 of the valve-piston to move away from seat I5 in ring I6. The steam then will be blown off from annular chamber I8 through ring I8, chamber 20, and the discharge pipe 2 I. When the operator desires to discontinue the blow-off of steam, he will close Valve 29. The steam owing through the restricted orice will gradually build up the pressure in the cylinder 9 and against side I2b of piston I I and in pipe 28 which will preponderate the opposed pressure against side-portion |25 of the piston and gradually move the valve-piston to its seat and discontinue the blowoff of steam from chamber I8. The Valve-piston closes without hammering against the seat in the ring I6. This exemplies a blow-off valve which is closed by steam and spring pressure and is controlled for blowing oi the steam by discharging the steam to atmosphere under control of the operators valve 29,

A stem 34 is screw-threaded at 3l to the cap I0, extends inwardly through the coil spring 23, and is provided with an outer terminal 32 whereby it may be turned to bring the inner end of the stem into engagement with the inner end of a socket 33 in the valve-piston to lock the latter closed if there is a leak or break in the pipe line 28 between the blow-off valve and the operators valve. A stem 35 is screw-threaded at 3B through the casing 6 and provided with an outer terminal 31 by which it may be turned and an inner end which, when said stem is rotated in the casing, will abut against the inner end of the valve-piston and lock the latter in its open position for draining the blow-01T valve.

The valve casing 8 is provided with screwthreaded openings for connection to the pipe 28 at opposite sides for convenience in installation and the threaded opening not used is closed by a plug 39. The casing 6 is also provided with screwthreaded openings at opposite sides for the discharge pipe 2| for convenience in installation and the opening not used is closed by a plug 40.

The invention exemplies a blow-oii valve which is held closed mainly by steam pressure and is controlled by exhausting steam to atmosphere under control oi the remotely located operators valve, is simple in construction, and operates without hammering the valve-piston against its seat. It also exemplifies a blow-off valve with a valve-piston which eliminates the necessity of packing between the piston and the casing, since leakage from the inlet chamber will be into the cylinder which receives steam through the restricted ow duct. Such leakage can be used in lieu of the restricted ow duct, but the port provides for closer control of the restricted flow. The invention also exemplifies a blow-off valve controlled by the exhaust of steam to atmosphere which is provided with means for locking the valve-piston in its closed position in the event of leakage and for holding the valve for draining the valve casing.

The invention is not to be understood as restricted to the details set forth, since these may be modied within the scope of the appended claim without departing from the spirit and scope of the invention.

Having thus described the invention, what we claim as new and desire to secure by Letters Patent is:

Blow-off mechanism for boilers, comprising: a valve casing provided with an inlet chamber; an extension communicating with said inlet chamber for communicatively connecting the inlet chamber to receive blow-off from the boiler; a cylinder at one side of the inlet chamber; a valve seat at the other side of said inlet chamber and an outlet chamber for the discharge of the blow-oli; a valve-piston slidably mounted in the cylinder for engaging the valve seat and controlling the ilow of blow-oilE steam from the inlet chamber to the outlet chamber, provided with an inner side of predetermined area exposed to the pressure of blow-01T steam in the inlet chamber and an outer side having a greater exposed area in the end of the cylinder opposite the inlet chamber; a spring for urging the valve-piston to its closed position, restricted flow means for constantly conducting blow-oli steam through the valve-piston from the inlet chamber to the outer end of the cylinder to exert preponderating pressure against the valve-piston to hold it normally closed and cut off the flow of blow-off to the outlet chamber, means for controlling the valve-piston for discharging blow-off, including a single pipe connected to the casing and communicating with and for exhausting steam from the outer end of the cylinder, for opening the valve-piston, and a normally closed remote control valve connected to the pipe, for retaining pressure in the outer end of the cylinder for holding the valve-piston closed and for exhausting steam from the outer end of the cylinder through the pipe for opening the valve-piston to discharge the blow-olf steam, a stem screw threaded to one end of the casing for holding the valve-piston in its open position, and a stem screw threaded to the other end of the casing for holding the valve-piston in its closed position.

CHARLES G. LEARNED. EDWIN L. CULL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 493,774 Howes Mar. 21, 1893 572,297 Hennebohle Dec. 1, 1896 880,030 Learith Feb. 25, 1908 926,389 Collin June 26, 1909 1,146,012 Mason July 13, 1915 1,241,037 Shark Sept. 25, 1917 1,303,045 Dieter May 6, 1919 1,460,746 Carlstedt July 3, 1923 1,924,733 Brock Aug. 29, 1933 FOREIGN PATENTS Number Country Date 500,667 Great Britain Feb. 14, 1939 

